big refactoring of API system

API/requests/request.h

@@ -0,0 +1,69 @@
+//  SPDX-FileCopyrightText: 2023 Yury Gubich <blue@macaw.me>
+//  SPDX-License-Identifier: GPL-3.0-or-later
+
+#pragma once
+
+#include <memory>
+#include <optional>
+
+#include <QObject>
+#include <QString>
+#include <QVariantMap>
+#include <QNetworkReply>
+
+namespace Request {
+class Request : public QObject {
+    Q_OBJECT
+
+public:
+    Request (const QUrl& url);
+    virtual ~Request ();
+
+    void send (QNetworkAccessManager& manager);
+    void cancel ();
+    void setAuthorizationToken(const QString& token);
+
+signals:
+    void done ();
+    void success (const QVariantMap& data);
+    void error (const QString& error, const std::optional<QVariantMap>& data);
+
+protected:
+    virtual void aquireRequest (QNetworkAccessManager& manager);
+    virtual void initializeRequest ();
+    virtual void onSuccess (const QVariantMap& data);
+    virtual void onError (const QString& error, const std::optional<QVariantMap>& data);
+
+    std::optional<QString> validate ();
+    std::optional<QVariantMap> readResult ();
+
+    static bool validateResponse (const std::optional<QVariantMap>& data, const std::map<QString, QMetaType::Type>& structure);
+    static QUrl createUrl(QUrl base, const QString& path);
+    bool stateTerminal() const;
+
+    constexpr static const char * const json = "application/json";
+    constexpr static const char * const urlEncoded = "application/x-www-form-urlencoded";
+
+private slots:
+    void onFinished ();
+
+protected:
+    static const std::map<QString, QMetaType::Type> resultStructure;
+    enum class State {
+        initial,
+        sent,
+        responded,
+        cancelled
+    };
+    struct NetworkReplyDeleter {
+        void operator () (QNetworkReply* reply) {
+            reply->deleteLater();
+        }
+    };
+
+    State state;
+    QNetworkRequest request;
+    std::unique_ptr<QNetworkReply, NetworkReplyDeleter> reply;
+    bool emptyResult;
+};
+}